The elephant in the aeroplane

In Light Sport Aircraft (LSAs) and Recreational Aviation (RA) – indeed in all flying machines – weight is a key factor. In fact it could be said that weight is THE factor when it comes to light aircraft design – strong (meaning heavy) enough to do the job, yet light enough to carry a reasonable load within the legal regulations of its category. Of all categories, LSAs and RAs have probably the most stringent weight limits applied to them.

Yet in almost all LSA/RA flight reviews I read, there is little or no mention of usable load, empty weights or maximum gross weights. How come nobody discusses this key topic – the elephant in the room? The aircraft may look and fly great but if the usable load is so limited that carrying a couple of typically sized people and a reasonable amount of fuel will take you outside the legal limit for the aircraft – what use is it?

At the recent Avalon Airshow, I wandered around looking at a wide selection of LSA and RA offerings. Many of them were kind enough to display data including empty and maximum weights alongside the aircraft.

All the aircraft I looked at posted a maximum gross weight of 600 kgs or, in a couple of cases, 550kgs and 544kgs. There was a seaplane with a maximum of 650kgs.

The declared empty weights varied between 312kgs and 530kgs although one of them went to the trouble of blanking out the empty weight for some reason. Excluding the anonymous empty weight and the 530kgs machine, the average empty weight of all the LSA/RA aircraft I photographed worked out at a whisker over 360kgs.

One well-known LSA showed – for what appeared to be identical models – empty weights of 360kgs and 390kgs. What, I wondered, could make such a large difference? there appeared to be no parachute rescue system in either, so I (at least) was puzzled.

So let’s have a look at usable loads. Taking a maximum gross of 600kgs, minus the average 360kgs empty weight, leaves you with 240 kgs for fuel, people and baggage. Typical pilots these days tend to weigh in at around 95+ kgs, passengers anything from 60 -100kgs+ – a total for people from around 165-195kgs. Some would say I’m being optimistic! I have certainly seen two big 100kgs+ people get out of an LSA on many occasions. But let’s stick to an average of 180kgs total for people. That legally leaves about 60kgs for fuel and bags. Fuel weighs around 0.72kgs per litre, so without bags you have about 80 litres of fuel. As an absolute minimum, you probably need to allow at least 5kgs for ‘bags’ – remember, tie-down kit, maps, aircraft cover, removable navigation/GPS equipment, headsets, cameras, clothing etc all count as ‘bags’.

Worst case scenario: your aircraft empty weighs 390kgs – see above. You weigh around 100kgs with your boots, headset and clothes on, your passenger the same. You’ve got a 2kgs tie-down kit in the back and your trusty portable GPS on board, plus your passenger’s camera kit. It all adds up to well over 590kgs – leaving less than 10 kgs for fuel, or around 13-14 litres….any more and you’re flying illegally in a 600kgs maximum gross aircraft.

So, what can you do with the elephant? Setting aside the regulations for the class, which lay down maximum empty weight limits based on engine power and number of seats, what implications does this have for buyers and, in particular, flying schools, who want to stay within legal load limits?

First, make sure, before you buy, what is the actual empty weight and thus the usable load. Beware of statements like ‘from 295kgs’ as this weight is often an absolute factory minimum, with no oil, or battery, or bigger ‘standard’ wheels/tyres, wheel spats, radio, antenna, even (in one case I know of) seat cushions and flight instruments. Don’t accept assurances that the factory already weighed your aircraft so you don’t need to – I know of a number of occasions where a repaired aircraft had to be re-weighed and came in much heavier than before repair – in one case somehow gaining over 40kgs (yes, really!) compared with the original factory weight sheet.

Get a written guarantee of the empty weight of the aircraft you’re buying or ask for the aircraft to be weighed just before you take delivery, it’s worth the money – and remember, the manufacturer wants to sell you an aircraft and won’t be the one copping it when you get ramp-checked, or the insurance company refuses to pay out because the plane was flying over the legal weight limit. Or your flying school is audited with a random weight check.

Next, work out your true weight and that of your passenger/co-pilot – including boots/shoes and clothing. Add that to the real aircraft empty weight to work out how much fuel and baggage you can carry. Can you still carry full fuel as well as people and bags? If not how much are you prepared to compromise? Personally, I have a 2-3 hour bladder, so I don’t often need full (fuel) tanks. But what about that 2-hour flight to a place with no fuel, plus the journey home?

Even if you and your passenger are quite light, remember that when you come to sell the aeroplane, the customer might be a flying school, or a lot heavier than you, potentially limiting your sales options.

There’s another one I hear a lot: ‘the plane’s safe to 750kgs gross, so you don’t need to worry’. But you DO. Safe it may be, legal it’s not…remember ramp checks and insurance companies?

Last but not least is the issue of centre of gravity (CofG). The CofG limits are calculated to fit in with the maximum gross weight of the aircraft – how many owners/pilots of LSA/RA aeroplanes actually calculate the CofG before taking their (maybe slightly heavier) friend for a quick morning flight? Tanks full? Feels a bit slow to lift off? Or maybe too quick, with a rearward CofG? No problem, the plane will fly OK…until it doesn’t. Read some accident reports about exceeding CofG limits.

Some people might feel I’m being a bit picky – after all, how often do you get ramp checked? Or insurance companies weigh the aircraft before paying out? Actually, surprisingly often. But the laws of physics can’t be denied; if you frequently fly at or over the aircraft weight limit, it will wear out much quicker. Safety margins are compromised and the flying characteristics will become more and more like a heavier GA-type aircraft. The cruise will be slower, the stall will be higher and you stand much more chance of bending the landing gear if you come down a bit heavy.

Ignorance of the true empty weight of your aeroplane is no defence. Don’t ignore the elephant! You have been warned!

Glider towing with the A22LS Foxbat

Sunday 17 March 2017 dawned clear and a relatively cool 20 celsius at Tyabb Airport. My friend Mike Rudd and I were flying that morning up to Benalla, north of Melbourne, to submit our A22LS Foxbat demonstrator to the Gliding Club of Victoria to test-tow a couple of gliders.

The flight from Tyabb to Benalla was uneventful except for a thick smoke haze up to about 6000 feet due to the smouldering remains of some large bushfires in the area and an almost total lack of wind. About an hour and 20 minutes after take-off, were touching down at Benalla. Gliders were already in the air, albeit in much smaller numbers than the last time we visited, just over 3 years ago.

I flew a short acclimatisation flight with Rob Pugh, the tow pilot for the day (I am not licensed to tow); he made one of the smoothest landings I have experienced in someone who had never flown the type before. Very reassuring for the remainder of the morning! Rob then did a couple of circuits on his own to check out the Foxbat handling without my 85 kilos of ballast in the passenger seat – anyway, towing is only permitted with one person on board.

The first glider – a single seat SZD51 Junior with gliding instructor Steve Hobby on board – was hooked up and, with GoPros activated on the Foxbat, Rob applied full power and took off. Temperature on the ground was about 30 Celsius (about 85-86 Fahrenheit), giving a density altitude at ground level of well over 2500 feet. There was almost no wind at all. Tow time to 2000 feet AGL (2500 feet on the QNH, about 5750 density altitude) was almost exactly 6 minutes and Rob was back on the ground just over 3 minutes later.

Next up was a 2-seat Twin Astir glider with just one person on board. This glider is affectionately known as the ‘concrete swan’ – the heaviest 2-seater in the club, so it would be interesting to see how long it took for the trip. In the event, tow time to the same altitude took only 30 seconds longer and Rob was back on the ground again, around 3 minutes after release.

We are making a short video of the test-towing which will be uploaded to our YouTube channel shortly. Meanwhile, Rob had a few candid comments about Foxbat towing. “Of course”, he told us, “with only 100hp available, the Foxbat won’t be competing with our Pawnees [my note: one of which has a liquid cooled Chevrolet V8 engine!]. But the Foxbat performed very well, considering the lack of wind and the high density altitude. The total take-off to landing times of just over 9 minutes worked out much better than the 13-14 minutes we were expecting. I think the high lift wing really helps it outperform many other Rotax engined types when towing”.

Successful glider towing is a complex equation – it’s not just how long it takes to reach altitude, it’s also the total air time on the tug (based on which, the glider pilot/customer pays), fuel costs, maintenance costs and any depreciation costs on the aircraft tug – many club towing aircraft have been written down to zero in value over the years.

However, the overall exercise was to determine how well the A22LS Foxbat performed – and the answer seems to be ‘much better than expected for such a small aircraft’. This feedback, together with excellent reports from other countries using the A22 for glider towing, confirms our belief that the aircraft will handle 75-80% of  typical towing tasks at around a third of the costs.


Aeroprakt CEO at Avalon Airshow

Terrific news! Yuriy Yakovlyev, CEO of Aeroprakt, 2018 World Ultralight Champion and designer of the A22 Foxbat and A32 Vixxen aircraft will be joining us at the Australian International Airshow at Avalon Airport near Melbourne.

Show dates are Tuesday 26 February to Sunday 03 March – with trade days from Tuesday to Friday and public days Friday to Sunday. Yuriy will be with us from Tuesday to Saturday inclusive – come along to our static display at area EN13 near the main entrance and say ‘Hello!’.

Foxbat Australia will have a high spec A32 Vixxen and an A22LS Foxbat on display.

Next to us, our new venture partners, AeroEdge Pty Ltd, will be launching the DirectFly Alto 912TG in Australia.

We still have a few trade tickets left but hurry, it’s first come first served!

Flying with my grandchildren

On New Year’s Eve I spent the most wonderful day flying in a Foxbat with my grandchildren and their mother (my eldest daughter) and her partner. All the grandchildren wanted a second flight, so I must have been doing something right. But then again, it’s quite difficult to do something wrong in a Foxbat! What a magical day….

Click on the picture to view; enable HD and expand to full screen to enjoy to the max!



New Foxbat demonstrator flies over 13th beach

Here are a few short seconds of our new A22LS Foxbat demonstrator in flight. After less than a month in the air, it’s already completed 25 hours’ flying and is currently having its first maintenance check.

This is the first Foxbat demonstrator we’ve had which is fitted with an AirMaster in-flight electrically adjustable propeller – this one with Whirlwind blades. We are evaluating the propeller before formally offering it as an option – our first impressions are that take-off distance is shorter, and climb is significantly better than with the standard KievProp; economy is slightly better. We will also evaluate this propeller on the A32 Vixxen in due course, where in addition to take-off and climb performance, we are predicting an improvement in cruise speed.

The demo Foxbat aircraft is also fitted with a glider tow hook and we will be undertaking towing trials in the near future in Victoria, Australia. This aircraft has oversize wheels, a 30kgs ‘Kelpie’ metal luggage compartment with a side door and a ballistic rescue system. The icing on this demonstrator cake is a 2-axis Dynon autopilot which will be connected with a GPS as soon as we can keep the aircraft on the ground long enough to fit one!

Come and see this aircraft along with the A32 Vixxen at the Australian International Airshow, at Melbourne’s Avalon Airport from 26 February to 03 March this year.

As usual, either click on the image above or here to view the video: Foxbat over 13th beach

What’s in a (Foxbat) colour?

In Australia, Aeroprakt aircraft come in a range of ‘standard’ colours – white, yellow, orange, red and blue. We are lucky in being able to paint our aircraft these vibrant colours – something denied to composite aircraft builders, where differential heating of colours can wreak havoc on the strength of glass fibre and other composites.

Throughout the world, colours can signify different things, often with cultural and other connotations beyond their simple names.

Here are a few thoughts to ponder around the ‘standard’ colours of our aircraft.

Blue – has long been considered a spiritual colour, ‘the vault of heaven’, the colour of the sky. But the use of blue as a colour is comparatively recent in human civilisation, as natural blue pigments are relatively rare in nature. Blue is sometimes called one of the primary colours, although the idea of blue, red and yellow as primary colours is a modern and Euro-centric concept. The ‘classical primaries’ – white, black, red and yellow – excluded blue, which only really arrived in Europe in the 13th century, as ultramarine. Ultramarine was incredibly expensive, being derived from the semi-precious stone, lapis lazuli, and at one time ultramarine was even more valuable than gold. In Australia, blue Foxbats make up about 5% of the fleet.

Red – has been historically associated with aggression and courage. Not for nothing did the soldiers and commanders of the Roman empire wear red. But red can also signify love and fertility. In many countries brides wear red and the colour also signifies good fortune and happiness. In the Christian church, red signifies the blood of Christ; as a result, it was adopted by monarchs all over Europe as a sign of their power, and by merchants as an indication of status. And, as everyone knows, red aeroplanes fly much faster than other colours! In Australia, red Foxbats and Vixxens make up about 10% of the fleet.

Orange – was originally considered to be a shade of yellow by the Egyptians and only became the modern ‘orange’ (from the Sanskrit ‘naranga’) in the mid 16th century. Before that, in China and India, the colour took its name from saffron, not the citrus fruit. In many cultures, orange is considered a colour of spiritual transformation. For example, in Buddhism, orange is the colour of illumination, the highest state of perfection. In western civilisations, orange is seen as a combination of red and yellow, signifying creativity, warmth and change. In Australia, orange Foxbats and Vixxens account for just over 10% of the fleet and growing.

Yellow – in almost all cultures is associated with the sun, with gold recognised as the strongest yellow of all. To the ancient Egyptians, gold represented the flesh of the gods and was thus used extensively to decorate the tombs of the pharaohs. In Greek mythology, the sun-god Helios wore a yellow robe while riding his chariot across the heavens. But yellow also has some conflicts – on the one hand, sunshine, optimism and enlightenment, while on the other, pale yellow has sometimes been used to represent cowardice. But I always think of yellow as the most luminous colour of the spectrum, always attracting the eye to its presence. In Australia, yellow is the most popular colour for Vixxens, and in particular, Foxbats, where it represents over 40% of the fleet.

White – lead white, was in continuous production for over 2000 years. This, the purest of whites, is derived from the oxidation of metal lead into flakes of its oxide, hence the common name of ‘flake white’ in many parts of the world. However, this very toxic lead variant of white has now been completely superseded by non-toxic titanium white. There are almost as many different shades of white as there are stars in the sky. Technically, white is not a colour, as it is a combination of all colours. White usually signifies purity, innocence, and integrity and in western cultures it is common for brides to wear white at their wedding. In the majority of cultures, white also means the beginning of life, and in some it is used as a predominant colour for funerals, intended to signify the end of one life and the beginning of the next. In Australia, white is the second most popular colour for Vixxen and Foxbat aircraft, representing almost 35% of the fleet.

The remainder of our fleet is made up of various other colours – green is in a vivid minority of three, with blue-black, mid-grey, grey & white and dark red having one each.

Having given you some insights into the history and meanings of our base aircraft colours, it probably remains that individual choice of colour for a customer’s aircraft is more dependent on how easily they can be seen in the sky and their partner’s colour preferences! So I think yellow and white will remain the main choice of colour for some time to come – although orange is gaining in popularity all the time.

For more information on the history and meanings of colours, have a look at books like Chromatopia and The Story of Colour

Dan Johnson tests the A32 Vixxen

Light aviation’s guru blogger Dan Johnson grabbed the opportunity to test fly the newest FAA LSA-approved aircraft, the Aeroprakt A32 Vixxen.

Click the photo above or here to see the article and accompanying video: Dan flies the A32

You can read more – much much more – about all manner of light sport, recreational and ultralight aircraft on Dan’s blog: ByDanJohnson.